The invention relates generally to the field of lighting systems and, more particularly, to high-intensity discharge lamps.
High-intensity discharge lamps generally include an arc tube, end plugs sealed against and into opposite ends of the arc tube, lead wires extending through the opposite end plugs, arc electrode tips coupled to the respective lead wires inside the arc tube, and one or more seal materials between the various components. These lamp components are typically made of different materials to enable the lamps to withstand certain operational conditions, such as high temperature (e.g., 900° C. to 1200° C.), high-pressure (e.g., 15 psi to 6000 psi), and corrosive dosing materials (e.g., halides) inside the lamps. Unfortunately, these different materials have different coefficients of thermal expansion (CTE), which can lead to thermal stress and cracks during operation of the lamp. For example, the joint between a lead wire and the end plugs and/or the arc tube can be susceptible to thermal stress and cracks due to different CTEs of the lead wire, the end plugs and/or the arc tubes, and the seal material.
Accordingly, a need exists for a conductive and corrosion resistant lead system having a relatively close CTE match with the arc tube and/or end plugs.